Portable beverage containers are used to hold many types of beverages to include carbonated soft drinks, fruit drinks, and beer. It is well known to provide a protective internal liner for those containers made of metal such as aluminum or steel to help preserve the beverage within the container by preventing undesirable chemical reactions that would otherwise take place over time by direct contact of the beverage with the metallic container. For containers made of plastic, there is typically no internal liner provided because the plastic material is inherently non-reactive with respect to most types of beverages.
Many beverages are preferably consumed at relatively cold temperatures, for example, between about 36° F. and 50° F. For carbonated soft drinks and beer, consumers typically prefer these beverages to be chilled prior to consumption. Traditional chilling or cooling techniques include placing the containers in a chilled environment such as a refrigerator or cooler, and then serving the beverage once the beverage has reached a desired chilled temperature.
When the beverage is removed from the chilled environment, the beverage begins to quickly warm due to a combination of external heat sources including ambient heat of the surrounding environment, contact with warm surfaces such as the consumer's hand or the surface on which the container is placed, as well as radiant heat from the sun or other light sources. Heat transfer takes place through the walls, base, and top of the container to the beverage. Without some means provided for insulating the container, the beverage so quickly warms that, in many circumstances, it becomes undesirable or unfit for consumption.
There are a number of inventions that have been developed for purposes of insulating a beverage within the container such that it is maintained at a desired temperature prior to consumption. For example, it is well known to provide external thermal barriers, such as an insulating sleeve that is applied over the exterior sidewall of the container. It is also known to provide an insulated label on the sidewall of the container. There are a number of disadvantages to these traditional methods of insulating beverages. An insulating label/sleeve only covers the container sidewall, therefore leaving the bottom of the container exposed. For insulated labels, they are typically much thicker than a non-insulated label and, therefore, standard packaging line may have to be substantially modified to accommodate these special labels. For insulating sleeves, these require the consumer to maintain a separate component to maintain the beverage at a desired cold temperature.
Some efforts have been made to provide an internal insulating liner for containers. One example is disclosed in U.S. Pat. No. 6,474,498. This reference discloses a thermally insulated container for canned beverages including a lining formed from a plastics material. The preferred embodiments suggest using a plastic closed cell material to include closed cell material similar to bubble wrap. The liner is intended to be placed into the container as by a slidable fit within the container so as to be in contact with the cylindrical inner surface of the container wall. The lining member may include an adherent surface allowing the lining to adhere to the internal wall of the container. In an alternative embodiment, this reference discloses a closed cell material that can be provided as a layer on the interior surface of the metal container in addition to or in place of a conventional lacquered coating applied to the interior surface of the container.
U.S. Patent Application Publication No. 2006-0073298 discloses a multi-layer inner liner provided for a container and an extrusion method for a beverage container. The method contemplates blow molding the inner liner by co-extrusion of a first inner layer of a thermoplastics material and a second inner layer made of a foam material having insulating properties. The inner layer of foam is further disclosed as having micro-spheres that expand during the blow-molding process.
U.S. Patent Application Publication No. 2006-0054622 discloses an insulated beverage container having an inner liner that adheres to the inside of the container. The inner liner is made from a crystalline ceramic material.
In addition to externally mounted sleeves and internal liners, some efforts have also been made to maintain beverages at a desired temperature by use of phase change material that is placed within the container. Upon warming, the phase change material changes phase to help maintain the beverage at a cooler temperature for a period of time in which the consumer would normally consume the beverage.
Phase change materials are substances with a high heat of fusion. These materials are capable of storing or releasing large amounts of energy. Phase change materials used for containers are solid/liquid change phase materials wherein the phase change material changes phase from solid to liquid at the material's melting point. More specifically, when the beverage is maintained in a chilled environment below the melting or phase change temperature, the phase change material remains in a solid state. When the container is removed from the chilled environment during consumption of the beverage, the phase change material absorbs a relatively large amount of heat without a significant rise in temperature. Thus, phase change material absorbs heat from the surrounding beverage in the container thereby keeping the beverage at the preferred drinking temperature longer.
One reference disclosing use of phase change material in a container includes the British Patent GB2370629. A phase change material is contained in a small chamber such as a tube placed inside the container. The phase change material is activated when the user opens the can. The phase change material is preferably a liquid, such as water, that boils or vaporizes in the tube. A lower pressure area or vacuum in the tube allows the phase change material to vaporize. Upon vaporization, heat is transferred from the beverage to the tube containing the phase change material.
International Publication WO9724968 discloses a self-cooling food or beverage contained in which a phase change capsule, when activated, results in heat exchange contact with the surrounding or adjacent food or beverage container.
U.S. Patent Application Publication No. 2006/0156756 discloses a self-cooling food or beverage container wherein the container has inner and outer walls and phase change material is located in the space between the walls.
While the foregoing references may be adequate for their intended purpose, there is still a need for providing a cooling element that can be used with a container wherein the cooling element can be easily incorporated into standard manufacturing and production lines without significant alteration to these processes. Furthermore, there is still a need to provide a cooling element for a container wherein the cooling element can be manufactured and installed at a relatively low cost so that the ultimate retail price of a container is still competitive with containers not incorporating cooling capabilities.
There is also a need for an internal thermal barrier to maintain a beverage at a desired temperature wherein the thermal barrier can be incorporated within a liner applied using standard packaging machinery. Further, there is a need to provide a thermal barrier liner for a container wherein the barrier liner can be expanded to cover not only the container sidewall, but also the bottom of the container.